Heretofore, in a thin card with a built-in IC chip, for example, an IC card, various IC chip modules in which connection terminals of an IC chip is connected to a connection pattern of a circuit board are utilized. In this type of IC chip modules, the IC card itself is not so expensive. Accordingly, since the IC chip modules must be manufactured as cheap as possible, a single-sided board having a connection pattern formed on one side of the circuit board is utilized and the IC chip is generally bonded and fixed on another side of the single-sided board. Various processes for bonding and fixing the IC chip to the circuit board and for electrically connecting connection terminals of the IC chip and the connection pattern of the circuit board have been proposed.
In a conventional IC chip module, referring to FIG. 7 through FIG. 9, a process for bonding and fixing an IC chip and a circuit board, and a process for electrically connecting connection terminals of an IC chip and a connection pattern of a circuit board will be explained.
FIG. 7 is a side view showing one example of a conventional IC chip module. The IC chip module 100 utilizes a board made from a thermosetting resin as a substrate 101. An IC chip 106 is bonded to the substrate 101 by an adhesive 105. In order to electrically connect connection terminals of the IC chip 106 and a connection pattern 103, after exposing the connection pattern 103 by forming connection holes 107 in the substrate 101 of the circuit board 104, the connection terminals of the IC chip 106 and the connection pattern 103 are electrically connected via wires 108.
FIG. 8 is a side view showing another example of a conventional IC chip module. The IC chip module 110 utilizes a board made from a thermosetting resin as a substrate 111. In order to electrically connect connection terminals of the IC chip 116 and a connection pattern 113, after exposing the connection pattern 113 by forming connection holes 117 in the substrate 111 of the circuit board 114, solder bumps B and the connection pattern 113 are electrically connected by solder in the connection holes 117. In order to bond the IC chip 116 to the substrate 111, an adhesive 115 is applied to a periphery of the IC chip 116 after the solder bumps B and the connection pattern 113 are electrically connected as described above.
Further, FIG. 9 is a side view showing the other example of a conventional IC chip module. The IC chip module 120 utilizes a board made from a thermosetting resin as a substrate 121. In order to electrically connect connection terminals of an IC chip 126 and a connection pattern 123, and in order to bond the IC chip 126 to the substrate 121, the connection pattern 123 is exposed by forming connection holes 127 in the substrate 121 of the circuit board 124. After electric conductive paste 128 is applied in the connection holes 127, bumps B are positioned and the electric conductive paste 128 is thermoset. Accordingly, the bumps B and the connecting pattern 113 are electrically connected. Then, the IC chip 126 is bonded to the circuit board 124 by applying a thermosetting adhesive 125 to a periphery of the IC chip 126 and by thermosetting the adhesive 125.
However, in each of the above described conventional IC chip modules 100, 110, 120, a thermosetting resin such as a glass-epoxy resin is utilized as a substrate 101, 111, 121 of the circuit board 104, 114, 124. Generally, the thermosetting resin is expensive. Accordingly, the problem arises in that the costs of the IC chip modules 100, 110, 120 is increased.
Further, in order to connect the connection terminals of the IC chips 106, 116, 126 and the connection patterns 103, 113, 123, the connection holes 107, 117, 127 must be formed in the substrate 101, 111, 121. Accordingly, the processes for manufacturing the conventional IC chip modules 100, 110, 120 become complicated and the costs are increased because a connection hole forming process is required.
Furthermore, in order to bond and fix the IC chips 106, 116, 126 onto the circuit boards 104, 114, 124, adhesives 105, 115, 125 are additionally required. Accordingly, the costs of the IC chip modules 100, 110, 120 are increased in accordance with the amount of the adhesives 105, 115, 125.
The present invention has been made in order to solve the above described prior problems. An object of the present invention is to provide an inexpensive electronic part module and a process for manufacturing the same wherein an inexpensive thermoplastic resin is used as the substrate of the circuit board, the connection holes need not be formed in the substrate when the bumps of the electronic part such as an IC chip and the like are electrically connected to the connection pattern, and the substrate itself is utilized as an adhesive.